New York gubernatorial candidate Rob Astorino ripped New Jersey Gov. and fellow GOPer Chris Christie Wednesday for appearing with rival Democratic Gov. Cuomo at a joint bistate security press conference at 7 World Trade Center — in the heat of an election campaign.

Christie, who is chairman of the Republican Governors Association, is supposed to help elect GOP candidates to head statehouses across the country — not undermine them, the Astorino camp said.

The election takes place Nov. 4.

“It’s beyond us why Governor Christie would want to spend so much time with Andrew Cuomo, who is under investigation by federal prosecutors, got caught cheating on his property taxes and has an approval rating that plummeted to 42 percent,” said Astorino spokeswoman Jessica Proud.

“Maybe he’s having 2012 flashbacks, but someone should remind him he is chairman of the RGA, not the DGA.”

The furor comes almost two years after Christie caught GOP heat for appearing with President Obama to survey damage along the Jersey Shore in the aftermath of Hurricane Sandy — just days before the Democratic incumbent’s re-election bid against Republican Mitt Romney. The move alienated many GOP leaders, but Christie defended the tour as helping his constituents.

Christie’s office dismissed the friendly fire from Astorino, and appeared baffled by it.

“This is a serious task between neighboring states, which suffered the worst terrorist attack in modern history. He can’t be serious,” said Christie spokesman Michael Drewniak.

Cuomo spokesman Matt Wing responded: “Politicizing public safety during a period of increased terrorist activity abroad is irresponsible and reckless.”

Christie, who was re-elected last year in a blue state and is eying a run for president, has stumped for other GOP gubernatorial hopefuls nationwide, but has not campaigned with Astorino, who is trailing Cuomo by double digits.

“We don’t pay for landslides and we don’t invest in lost causes,” Christie said of Astorino in July.

At the time, Astorino said Christie should step down as RGA chief if he won’t support his campaign against Cuomo.

The New York race is a tricky situation for Christie, who wants to woo Republicans nationally but has to work with Cuomo on bistate issues in their respective roles as governors. The two jointly oversee the Port Authority, for example.

At Wednesday’s press conference, they announced there will be a surge of law enforcement and military personnel at area mass transit hubs — subways, PATH trains, and LIRR and Metro-North railroads — due to heightened tensions in the Middle East.

Cuomo and Christie on Wednesday signed a bi-state agreement to boost security to combat terrorism.